1. Field of Invention
This invention relates to a display panel and a display device and, in particular, to a display panel and display device having higher reliability.
2. Related Art
By taking a conventional liquid crystal display (LCD) panel as an example, it includes a thin film transistor (TFT) substrate and a color filter substrate which are disposed oppositely. The TFT substrate includes a plurality of TFTs and a plurality of pixel electrodes which are both disposed on a substrate. The TFTs can be controlled so that the data can be inputted to the pixel electrodes, and thereby the orientation of the liquid crystal can be controlled for the image display.
Due to the raised market competition, the requirements about the size of the display panel or device and the color saturation of the display are rapidly increased as well as the demands for the performance and stability of the TFT. Accordingly, the TFT having metal oxide-based (MOSs) as the material of the semiconductor layer can be manufactured under the room temperature and possess well current output characteristic, lower leakage current and better electron mobility that is ten times higher than the amorphous silicon TFT (a-Si TFT), so as to reduce the power consumption of the display panel and raise the operation frequency of the display panel. Therefore, the metal oxide-based TFT has become the mainstream driving element in the display panel and device.
However, although the metal oxide-based semiconductor layer has better electrical property, it is easily affected by the moisture and oxygen and thus will worsen the reliability of the display panel. Moreover, the material of the organic flatting layer introduced into the high resolution product for increasing the aperture ratio of the display panel has weaker ability to block the moisture than the inorganic material, so that it may absorb the moisture in the manufacturing process to affect the reliability of TFTs and other elements disposed within the active area. Accordingly, in the conventional art, an inorganic insulating layer will be disposed to cover the organic flatting layer to block the moisture so that the organic flatting layer can be prevented from absorbing the moisture and thus affecting the element's characteristic. However, if the organic flatting layer has absorbed the moisture during the process, the moisture may be blocked and thus not be scattered due to the covering of the inorganic insulating layer, and therefore the element's characteristic of the display panel will be affected and the reliability of the product will be thus reduced.